This study reports the results of a battery of physical function tests used to assess physical function of older patients with clinical knee and/or hip osteoarthritis (OA), and the correlation to the WOMAC Index (disease-specific questionnaire). A total of 106 sedentary subjects, aged >60 years (mean 69.4, S.D. 5.9) with hip and/or knee OA (mean 12.2 yrs, S.D. 11.0) participated in the study. Mobility, joint flexibility and muscle strength were evaluated by recording time to: walk a distance of 8', ascend/descend 4 stairs, rise from/sit down from a chair (5 times). Hip/knee flexion and isometric quadriceps strength were also measured. Categories of performance were formed by dividing data into quartiles for each test (1=highest, 4=lowest score, 5=unable to complete) and, by summing the category scores, a total summary score (TSS) was obtained. The battery of physical function tests showed an acceptable test-retest reliability (ICC of all tasks > or =0.80) and internal consistency (Cronbach's alpha > or =0.80). Performance scores on walking, stair climb, chair-rise and ROM of affected OA joints were significantly correlated with each other, and with the WOMAC Index (P<0.05, Spearman's correlation). Lower scores on the TSS were associated with lower scores on all the WOMAC Index items (P<0.001). This study shows that a simple battery of physical function tests in combination with the WOMAC Index are reliable and may be useful outcome measures in the evaluation of therapeutic interventions and geriatric rehabilitation.